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Absorption Coefficient of a Double-Layer Inhomogeneous Micro-perforated Panel Backed with Multiple Cavity Depths
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Double-layer micro-perforated panels (MPPs) have been studied extensively as sound absorption systems to increase the absorption performance of single-layer MPPs. However, existing proposed models indicate that there is still room for improvement regarding the frequency bands of absorption for the double-layer MPP. This study presents a double-layer MPP formed with two single MPPs with inhomogeneous perforation backed by multiple cavities of varying depths. The theoretical formulation is developed using the electrical equivalent circuit method to calculate the absorption coefficient under a normal incident sound. The simulation results show that the proposed model can produce absorption coefficient with wider absorption bandwidth compared with the conventional double- and even triple-layer MPPs. The bandwidth can be increased to higher frequency by decreasing the cavity depth behind a sub-MPP with small hole diameter and a high perforation ratio, and to lower frequency by increasing the cavity depth behind a sub-MPP with large hole diameter and a small perforation ratio. The experimental data, measured by impedance tube, are in good agreement with the predicted results.

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Publication Date
Sat Dec 17 2022
Journal Name
Iraqi Journal Of Laser
PDF Study the Effect of Nano Aluminum Oxide Coating on PMMA as Thermal Insulator: Dawood Obied Altiafy *, Hussien Ali Jawad, Noor Taha Ismaeel
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Abstract: In the present work, the heat transfer of Nano Aluminum Oxide -NAO- has been studied practically to define the appropriate insulation conditions.  This study focuses on finding of the amount of heat transfer through a glass substrate that is coated with nanoalumina doped on PMMA matrix. The optical and thermal properties were systematically investigated. The density of heat flow rate, was calculated in the range values (240-260) W/m2 while the optimum values confine between (250-260) W/m2 at temp. (25-35)Co. The results showed that the thermal insulation of the sample was significantly enhanced at temp. (30-50)Co. The simulated net heat transfer through window decreased linearly with incr

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Publication Date
Mon Jun 24 2024
Journal Name
International Tinnitus Journal
Distribution of HPV Genotypes 16 and 18 among Resected Tonsillar Tissues from Pediatric Patients Operated for Non- Oncologic Nasopharyngeal and Palatine Tonsillar Hypertrophies
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Background: Recent advancements in molecular techniques have identified over 450 genotypes of Human Papillomavirus (HPV), classified into low- and high-oncogenic risk categories. The rise in high-oncogenic risk HPV genotypes has been linked to various cancers, including those affecting the oral, oropharyngeal, and nasopharyngeal regions in both pediatric and adult populations. Methods: In this study, a cohort of 102 tonsillar tissue samples was included. This comprised 40 specimens from pediatric patients aged 4 to 9 years with nasopharyngeal adenoid hypertrophies, and 42 specimens from pediatric patients aged 5 to 12 years with palatine tonsillar hypertrophies. Among the 82 tonsillar tissue samples analyzed, 38 were from pediatric patients

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Publication Date
Sat Oct 28 2023
Journal Name
Baghdad Science Journal
New Records of Non-Diatom Algae in Aquatic Habitat along Greater Zab River Path from Bekhma to Gwer District in Erbil Province, Iraq
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A study of non-diatom algal species composition in twelve sites from Greater Zab River path within
Erbil Province, was carried out from April 2021 to January 2022 with monthly sample collection in twelve studied sites. Among them site 4,5,6,7 and 9 are the first for algal study in this area. The 112 different species of algae belong to 33 genera, 25 families, 13 orders and 4 divisions have been identified. The predominant genera included Spirogyra and Cosmarium 17, 8 taxa respectively. 13 taxa were new recorded to Iraqi
Kurdistan algal flora and 9 of them were new recorded to Iraqi algal flora: Botryosphaerella sudetica, Muriella magna, Gloeotaenium loitlesbergianum, Apiocystis brauniana, Anabaena oscillarioides, C. distentum

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Publication Date
Thu Aug 01 2024
Journal Name
Materials Science In Semiconductor Processing
Enhancing charge transfer in 0D/2D cobalt sulfide/boron-doped graphitic carbon nitride heterojunction photocatalyst for degradation of organic pollutants under LED illumination
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Semiconductor-based photocatalytic processes are widely applied as ecofriendly technology for degrading organic pollutants. Establishing photocatalytic heterojunctions with Z-type photocarriers transfer pathways is projected to be a superb strategy to enhance photocatalytic behavior. In this paper, novel and stable (0D/2D) heterojunctions of CoS-embedded boron-doped g-C3N4 (CoS/BCN) with a high rate of charges transfer/separation were assembled for degradation of malachite green dye (MG). The CoS/BCN photocatalyst achieves a photodegradation efficiency of 96.9 % within 1 h of LED illumination, which is 2.5 and 1.4-fold enhancement compared with bare g-C3N4 and BCN, respectively. Besides, the results of species-trapping trials exhibited that

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Publication Date
Mon Aug 01 2016
Journal Name
Iosr Journal Of Dental And Medical Sciences
Evaluating the Effect of Showing the Dental Injector to Children on Their Dental Behavior in Relation to the Vital Signs And Maternal Anxiety
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Publication Date
Thu Mar 31 2022
Journal Name
American Journal Of Economics And Business Management
Measuring and Analyzing the Factors Affecting the Behavior of Government Spending in Iraq Using the Co-Integration Test for the Period 2000-2020
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Government spending is the tool that the state uses to achieve its various goals. The research aims to identify the most important determinants of government spending in Iraq and to indicate the type and nature of the relationship between government spending and its determinants, which will contribute to understanding the movement of government spending. The results of the co-integration test using the border test methodology showed that the variables of population growth and oil prices have a long-term effect on government spending while inflation is not significant in the long run, and that 47% of the equilibrium imbalance (short-term imbalance) in government spending in the previous period (t-) can be corrected in the current period (t)

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Publication Date
Fri Jun 10 2022
Journal Name
V. International Scientific Congress Of Pure, Applied And Technological Sciences
Synthesis and characterisation of new Co(II), Zn(II) and Cd(II) complexes derived from oxadiazole ligand and 1,10-phenanthroline as co-ligand
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SYNTHESIS AND CHARACTERISATION OF NEWCo(II), Zn(II) AND Cd(II) COMPLEXES DERIVED FROM OXADIAZOLE LIGAND AND 1,10-PHENANTHROLINE AS Co-LIGAND

Publication Date
Wed Dec 12 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Relationship between Third Trimester Vaginal Bleeding Medical Causes and pregnancy Outcomes of Pregnant Women Attending Bint Al-Huda Hospital in Al-Nasiriya City
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Objective: To find out the relationship between vaginal bleeding during third trimester and pregnancy outcomes. Methodology: A purposive sample is "Non-probability" of (100) women who had diagnostic vaginal bleeding during third trimester (27-40wk) of pregnancy, and who visited the Bint Al-Huda Hospital for the period from 15th Feb. to 17th May 2015.Validity and reliability of questionnaire are determined through pilot study. Descriptive and inferential statistical procedures were used to analyze the data, and the data were collected by using interview technique, constructed questionnaire has been desig

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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Violet Laser Irradiation Effect on The Optical Properties of Cobalt oxide (CoO<sub>2</sub>) Thin Films deposited via Semi-Computerized Spraying System
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Abstract<p>The existing investigation explains the consequence of irradiation of violet laser on the optic properties of (CoO<sub>2</sub>) films. The film was equipped by the utilization of semi-computerized spray pyrolysis technique (SCSPT), it is the first time that this technique is used in the preparation and irradiation using a laser in this technique. From the XRD analysis, the crystalline existence with trigonal crystal system was when the received films were processed by continuous violet laser (405 nm) with power (1W) for different laser irradiation time using different number of times a laser scan (0, 6, 9, 12, 15 and 18 times) with total irradiation time(0,30,45,60,75,90 min</p> ... Show More
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Publication Date
Sat Feb 09 2019
Journal Name
Journal Of The College Of Education For Women
The Effect of Combining Video Lectures and Kolb Experiential Learning on EFL Student-Teachers’ Ability to Teach Communicative Coursebook and their Teaching Competencies
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Communicative-based textbooks are developed and disseminated throughout the country.
However, it is difficult for teachers who themselves have learnt English through the traditional
approaches to suddenly be familiar with CLT (Communicative Language Teaching) principles
and teach communicatively. Therefore, many teachers remain somewhat confused about what
exactly CLT is and others familiar with CLT but unable to achieve communicative classroom
teaching. Consequently, those teachers need to be introduced to the CLT principles and they need
training in how to put CLT principles into practice. Accordingly, this study aims to find out the
effect of combining video lectures and Kolb experiential learning on EFL student-t

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